Ruby is an important tool to have around, Mac OS X already comes bundled with it, but sometimes you need a different version. Mavericks now comes with Ruby 2.0.0-p195, any previous ones comes with 1.8.7 which is very close to end of life. There are lots of alternative to install multiple version of Ruby on your workstation, rvm or rbenv works well for this job but Postmodern have another angle to this problem. Quite similar to the Arch Linux Kiss (Keep It Simple, Stupid) philosophy, chruby is a deadly simple tool to do just that by updating the environment variables: $RUBY_ROOT, $RUBY_ENGINE, $RUBY_VERSION, $GEM_ROOT, $GEM_HOME, $GEM_PATH and $RUBYOPT in just 90 lines of codes. Let’s details how you can install it on your Mac.